After upgrading to the current Raw Hide XFree86 packages and rebootings, I got a
bunch of errors on my console during reboot when xfs started up, about
unrecognized tokens in files in /usr/X11R6/lib/X11/fonts/encodings/large. Alas,
I could not capture them because they were sent to stderr instead of the boot
log, and I cannot duplicate the problem now, so I don't know exactly which part
of the xfs startup is causing it. Also, when I rebooted a second time the
errors did not recur.

Hmm. Unable to produce so far.. It's important with rawhide bug reports
to indicate the exact version-release of the package you're reporting
the bug for, and in upgrade failure cases, to also report the ver-rel of
the package that was being upgrade.
If you could paste a log or something of the errors, it might be useful
to track down any problem.

It's difficult for me to provide a log because the problem happens at reboot.
But the next time I update XFree86 I'll restart xfs by hand in a script shell
and see if I can duplicate it there.
The problem happened with two Raw Hide XFree86 updates in a row -- it wasn't
confined to a single Raw Hide version.